1. Field of the Invention
This invention relates to a traveling water screen with pans for dipping both fish and water from a stream. More specifically, the invention concerns an improved pan profile that facilitates flushing the pans with a low pressure spray of water and a method of doing the same.
2. Description of the Prior Art
Traveling water screens for the separate disposal of refuse and fish are described in U.S. Pat. No. 2,804,209 that issued to Carlton et al on Aug. 27, 1957, and U.S. Pat. No. 2,851,162 that issued to Bleyer on Sept. 9, 1958. Both of these patents show an endless belt type of traveling water screen that extends transversely of a water intake channel. The screen travels through a vertical loop for removing both refuse and fish from a stream of water in the intake channel. Above the top of the channel, on the upstream side of the screen, are devices for flushing fish from pans that are attached to the screen. The flushed fish are returned to the stream at a location remote from the screen.
The Bleyer patent shows a trough that discharges longitudinally through a discharge port at one end of the trough. There is no indication that the transverse profile of the trough could be utilized in the lateral flushing of fish from the trough. This patent also teaches that when fish are subjected to the action of high pressure cleaning jets or sprays they are frequently killed or seriously injured.
The Carlton et al patent shows a fish holding pan that is flushed by a spray of water directed transversely of the pan to flow about a curved bottom thereof. This patent shows a discharge lip formed by an outer edge wall of the pan that is inclined upwardly at an obtuse angle with the bottom wall of the pan. Such an inclined outer edge wall increases the depth of water retained in the pan after dipping in the stream, but such a wall also deflects upwardly the spray water flowing transversely about the pan bottom. Thus, the velocity of spray water flowing about the pan bottom is reduced, and the upwardly deflected water acts as a lateral barrier for water standing in the pan.